The interaction between ornamental succulents and the root-knot nematode (Meloidogyne spp.) is poorly known. Morpho-anatomical modifications induced by M. incognita to roots of Echeveria cimette and Pachyphytum compactum (Crassulaceae) were analyzed. The affected roots of both taxa showed: numerous galls with egg masses, hyperplastic reactions, cell suberization, disorganized vascular tissues, and development of multinucleated giant cells. Although both hosts were shown to be susceptible, certain characteristics evidenced plant defense reactions. In E. cimette, in those zones of the gall cortex that had great accumulation of tannins no females or egg masses were observed and this compound would be playing a role of a natural defense barrier. Suberized cells surrounding the egg masses could limit the movement of hatched juveniles. In P. compactum, the presence of branched roots with excessive atypical short extensions was noticeable. They were highly suberized and would act as a barrier preventing the loss of water and solutes; they might also be related to a defense mechanism, since they had tannins. Root cell studies of E. cimette and P. compactum parasitized by M. incognita are described for the first time. These results show the importance of commercializing ornamental plants with an adequate sanitary control to avoid the dispersal of this polyphagous nematode. Vegetative propagation of succulents is highlighted, since when they are affected by nematodes, the cuttings can be used as a resource for the conservation of plants.

观赏性多肉植物与根结线虫 ( Meloidogyne spp.) 之间的相互作用鲜为人知。分析了M. incognita对Echeveria cimette和Pachyphytum compactum （景天科）根的形态解剖学改变。两个类群的受影响的根表现为：大量虫瘿和卵块、增生反应、细胞木栓化、维管组织紊乱和多核巨细胞的发育。虽然这两种宿主都表现出易感性，但某些特征证明了植物防御反应。在E. cimette 中，在那些单宁大量积累的胆皮质区域中，没有观察到雌性或卵块，这种化合物将发挥天然防御屏障的作用。卵块周围的栓塞细胞可以限制孵化幼体的运动。在P. compactum 中，明显存在具有过多非典型短延伸的分枝根。它们高度栓塞化，可作为防止水和溶质流失的屏障；它们也可能与防御机制有关，因为它们含有单宁。首次描述了南方根结线虫寄生的E. cimette和P. compactum的根细胞研究。这些结果表明，通过适当的卫生控制将观赏植物商业化以避免这种杂食性线虫扩散的重要性。突出了多肉植物的无性繁殖，因为当它们受到线虫的影响时，插条可以用作植物保护的资源。